[1035] Serum level of HER2 extra cellular domain (ECD) is a significant prognostic factor for survival in metastatic breast cancer without HER2 overexpression on primary tumor.

Dinocca S, Blot E, Laberge-Le-Couteulx S, Menard J-F, Guillemet C, Veyret C, Basuyau J-P.. Centre Henri Becquerel, Rouen, France; CHU, Rouen, France

Introduction: This study evaluated the prognostic value of serum HER2 ECD level at the time of metastasis in breast cancer patients having a primary tumour without HER2 overexpression/amplification. Patients and Methods: One hundred forty-five patients treated for metastatic breast cancer between January 1999 and February 2005 at the Centre Rgional de Lutte Contre le Cancer de Haute Normandie were included in this retrospective study. Inclusion required available pre-treatment frozen serum at the time of metastasis and an initial tumour tissue without HER2 overexpression/amplification (0 or 1+ by immunohistochemistry). Serum HER2 ECD level was quantified using an ELISA test (Oncogene Science, Cambridge, MA). Normal HER2 ECD level was 15g/l as specified by the manufacturer. Results: Twenty-six out of 145 (18%) patients without HER2 overexpression/amplification in primary tumour had elevated serum HER2 ECD levels before treatment. In univariate analysis, the median survival for patients with elevated serum HER2 ECD level was significantly shorter (14.5 months) than for patients with normal serum HER2 ECD level (35.5 months) (p=0.001). Kaplan-Meier survival curves showed that elevated serum HER2 ECD level was statistically linked with survival (Figure). In multivariate analysis, delay 24 months between initial tumour and metastasis (p<0.001), visceral site of metastases (p=0.001) and elevated pre-therapeutic serum HER2 ECD level (p=0.03) were significantly linked with a worst prognosis. Conclusion: These results need further confirmation in prospective and larger series. If confirmed, it could suggest a potential interest for the use of trastuzumab in metastatic breast cancer with elevated serum HER2 ECD level even without HER2 overpression/amplification in the primary tumour.



Thursday, December 14, 2006 5:00 PM

Poster Session I: Prognosis and Response Prediction: Predictive Factors I (5:00 PM-7:00 PM)